Transparent and translucent crosslinked propylene-based elastomers, and their production and use

ABSTRACT

The present invention provides a crosslinked propylene-based elastomer having an isotactic propylene triad tacticity of from 65 to 95%, a melting point by DSC equal to or less than 110° C., a heat of fusion of from 5 J/g to 50 J/g, and a haze % per 100 mil thickness of 95 or less, and comprising at least 75 wt % propylene-derived units, at least 5 wt % ethylene-derived units, and optionally 10 wt % or less of diene-derived units. In an embodiment, the present invention is a blend of a continuous phase of the crosslinked propylene-based elastomer and a dispersed phase of a crystalline polymeric compound. The present invention also provides elastomeric compositions comprising a crosslinked propylene-based elastomer as described herein and 100 parts by weight or less of a pigment per 100 parts of polymer. The present invention also provides films, fibers, nonwovens, molded objects, and extruded forms which include any of the inventive compositions described herein.

This application claims the benefit of U.S. Provisional Application No.60/519,975, filed Nov. 14, 2003, the entire disclosure of which ishereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is directed generally to crosslinkedpropylene-based elastomers having an isotactic propylene triad tacticityof from 65 to 95%, a melting point by DSC equal to or less than 110° C.,a heat of fusion of from 5 J/g to 50 J/g, and a haze % per 100 milthickness of 95 or less. The propylene-based elastomers of the inventioncomprise at least 75 wt % propylene-derived units, at least 5 wt %ethylene-derived units, and optionally 10 wt % or less of diene-derivedunits. The invention is also directed to elastomeric compositionscomprising such a crosslinked propylene-based elastomer and 100 parts byweight or less of a pigment per 100 parts of polymer. Embodiments of theinvention also include films, fibers, nonwovens, molded objects, andextruded forms which include such compositions. Especially preferredembodiments and applications of the invention are those in which somemeasure of transparency or translucency is desired.

BACKGROUND

Amorphous and partially crystalline (generally referred to assemi-crystalline) polymers can provide elastomeric properties asdefined, for example, in ASTM D1566. An important class of elastomers isderived from polyolefins, generally using addition polymerization with aZiegler-Natta type catalyst system. Currently, polyolefin elastomers areinterpolymers of ethylene, a crystallinity-disrupting α-olefin such aspropylene, which provides short chain branches, and optionally smallamounts of a polyene, such as a diene, to provide unsaturated shortchain branches useful in providing crosslinks between different chains.These interpolymers may be ethylene propylene copolymers (EP) notcontaining units derived from diene, or ethylene propylene dieneterpolymers (EPDM).

Different technologies exist for curing EP and EPDM interpolymers.Curing can proceed progressively from an initial creation of long chainbranches where a macromer or polymer chain inserts itself along thelength of an already formed polymer, to an intermediate form in whichthe cured polymer is partly soluble and partly insoluble, to a fullycured form in which the bulk of it is insoluble and substantially allpolymer chains are linked into a network and no isolated polymer chainsremain for individual extraction.

A person skilled in the art selects the interpolymer, thecuring/crosslinking systems, and other formulation ingredients tobalance processability and physical properties of the final product suchas aging, hardness, extensability, compression set, tensile strength,and performance when cold.

EP 964641, EP 946640, EP 1003814, U.S. Pat. No. 6,245,856, and U.S. Pat.No. 6,525,157, and others disclose polyolefin interpolymers that areelastomers and have crystallinity resulting from isotactically-arrangedpropylene-derived sequences in the polymer chain. This is in contrastwith the EP and EPDM interpolymers in current commercial use whosecrystallinity is due to ethylene-derived sequences. The properties ofsuch propylene-based elastomers are different in many aspects from knownEP and EPDM interpolymer elastomers. Use of dienes for these newpropylene-based elastomers has been contemplated. See, for example, WO00/69964, including at page 15, lines 18 to 25.

SUMMARY OF THE INVENTION

In one aspect, the invention provides propylene-based elastomers whichare cured to various degrees so as to further enlarge the elastomericperformance envelope of the elastomers and permit convenient processing.

In another aspect, the improved propylene-based elastomer includes adiene to facilitate curing and optimal end use performance in variousoptions of formulation and processing.

In another aspect, the invention provides an improved formulationcontaining such propylene-based elastomer to provide appearance and enduse performance characteristics not achievable with EP and EPDMinterpolymer elastomers.

It has been surprisingly found that novel crosslinked propylene-basedelastomers can be prepared that are transparent or translucent and havehigh ultimate tensile strength and tear strength. In a particularembodiment, these crosslinked propylene-based elastomers have improvedultimate tensile strength and Die C tear strength compared tocrosslinked compositions made from commercially available EPDM.

In one embodiment, the invention provides a crosslinked elastomer havingan isotactic propylene triad tacticity of from 65 to 95%, a meltingpoint by DSC equal to or less than 110° C., a heat of fusion of from 5J/g to 50 J/g, and a haze % per 100 mil thickness of 95 or less. Thecrosslinked elastomer comprises at least 75 wt % propylene-derivedunits, at least 5 wt % ethylene-derived units, and optionally 10 wt % orless of diene-derived units.

In another embodiment, the invention provides an elastomeric compositioncomprising a crosslinked propylene-based elastomer as described hereinand 100 parts by weight or less of a pigment per 100 parts of polymer.

In another embodiment, the invention provides an article, such as afilm, fiber, nonwoven, molded object, or extruded form which includesany of the inventive compositions described herein.

DETAILED DESCRIPTION

Optical Properties

In the preferred embodiment, the present invention relates toelastomeric materials having good strength and tear properties whilealso having significant transparency or translucency. Preferredembodiments include a blend of one or more propylene based elastomersand a second polymer, most preferably isotactic propylene, with at leastone of the propylene based elastomer and the second polymer beingcross-linked. Transparency is measured as a maximum value of haze % per100 mil thickness of a sample of the material measured in the mannermore fully set out in “Test Methods”, below. The crosslinkedpropylene-based elastomer of the present invention, and compositions ofthe present invention which comprise such propylene-based elastomers,have a haze % per 100 mil thickness preferably of 95 or less, or 80 orless, or 60 or less, or 50 or less, or 40 or less, or 30 or less, or 20or less.

In an embodiment of the present invention, the compositions furthercomprise a non-black pigment. The pigment, though not significantlyaffecting the transparency of the crosslinked article, can impart a tintor color. The pigment may be any color, or tint, for example white, red,green, blue, or yellow.

Crosslinking

In one embodiment, the strength, tear resistance and other performanceproperties of the propylene-based elastomer are improved by crosslinkingthe elastomer to a preselected degree. In another embodiment, thepropylene-based elastomer is crosslinked to various degrees to permitconvenient processing. In certain embodiments, the propylene-basedelastomer includes a diene to facilitate crosslinking and optimal enduse performance in various options of formulation and processing. Inother embodiments, such as when using radiation to induce crosslinking,the presence of diene in the propylene-based elastomer is optional.

As used herein, the term “crosslinked” refers to a composition whereinthe polymer chains have been joined by one or more conventionalcrosslinking procedures so as to provide a composition having at least 2wt % insolubles based on the total weight of the composition and/or acomposition having a viscosity ratio of from 1 to 10. In a particularembodiment, the propylene-based elastomer is crosslinked to a degree soas to provide a composition having at least 2 wt %, or at least 5 wt %,or at least 10 wt %, or at least 20 wt %, or at least 35 wt %, or atleast 45 wt %, or at least 65 wt %, or at least 75 wt %, or at least 85wt %, or less than 95 wt % insolubles in any solvent that dissolves thecomposition prior to crosslinking. In another particular embodiment, thepropylene-based elastomer is crosslinked to a degree so as to providecomposition having a viscosity ratio of from 1.1 to 100, or, from 1.2 to50, or yet more preferably from 2.0 to 20 and most preferably from 5.0to 10.

Typically, the ultimate tensile strength of a particular material isaffected by the MFR of the uncrosslinked compound; e.g., those materialshaving a lower beginning viscosity (i.e., higher MFR) typically have alower ultimate tensile strength. It is therefore surprising that thecrosslinked propylene-based elastomers of the present have a highultimate tensile strength without having a high viscosity prior tocrosslinking. For example, in a particular embodiment, the crosslinkedpropylene-based elastomers of the present invention have an ultimatetensile strength (TS), of 0.5 MPa or greater, while having a startingviscosity of 25 MFR. In a particular aspect of this embodiment, theratio of the Shore A hardness to MFR@230° C. of the propylene-basedelastomer, prior to crosslinking, and the ultimate tensile strength(TS), measured in MPa, of the crosslinked propylene-based elastomer,satisfy the following equation: (Shore A hardness/MFR@230°C.)≦1.66*TS−B₁, where B₁ is 0, or 3.33, or 6.66, or 10.

Generally, the Die C tear strength of a material is affected by the MFRof the uncrosslinked compound; e.g., those materials having a lowerviscosity (i.e., higher MFR) generally have a lower Die C tear strength.Conversely, those materials which have a high Shore A hardness alsoinherently have a high Die C tear strength. It is therefore surprisingthat the crosslinked propylene-based elastomers of the present inventionhave a high Die C tear strength without having a high viscosity. Forexample, in a particular embodiment, the crosslinked propylene-basedelastomers of the present invention have a Die tear strength (Die C),measured in lb force/inch, of 50 or greater. In a particular aspect ofthis embodiment, the ratio of the Shore A hardness to MFR@230° C. of thepropylene-based elastomer, prior to crosslinking, and the Die C tearstrength, measured in lb force/inch, of the crosslinked propylene-basedelastomer, satisfy the following equation: (Shore A hardness/MFR@230°C.)≦0.2*Die C−B₂, where B₂ is 0, or 10, or 20, or 30.

The compositions described herein may be prepared by any procedure thatprovides an intimate mixture of the polymeric components. Generally, thefirst step of the process is mixing the polymeric components andoptional additives, such as process oil, fillers, colorants,antioxidants, nucleators, and flow improvers using equipment such as,but not limited to, a Carver press for melt pressing the componentstogether, internal mixers such as a Banbury mixer or a Brabender mixerfor solution or melt blending of the components, and equipment used forcontinuous mixing procedures including single and twin screw extruders,static mixers, impingement mixers, as well as other machines andprocesses designed to disperse the components in intimate contact. Acomplete mixture of the polymeric components is indicated by theuniformity of the morphology of the composition. Such procedures arewell known to those of ordinary skill in the art. In one embodiment, thenext step is mixing a chemical curative, such as peroxides or sulfurcompounds, with the intimate mixture, and then fabricating the intimatemixture including the chemical curative into the final shape of thearticle and raising the temperature for an extended period of time toallow the crosslinking of the propylene-based elastomer. In anotherembodiment, the next step is fabricating the intimate mixture into thefinal shape of the article, and then exposing the fabricated mixture toan external curative agent, such as high energy radiation, to inducecrosslinking of the propylene-based elastomer.

The curing systems that may be used in the practice of the inventioninclude one or more of sulfur based curatives, peroxide curatives, resincure, hydrosilation, labile or migratory cure systems, and high energyradiation. Such curing systems are well known in the art.

When using a chemical curing agent, such as sulfur, sulfur donors,peroxides, and resins, to induce the reaction, the curing agent isgenerally mixed into the propylene-based elastomer, or the blendcomprising the elastomer, prior to the fabrication of the final shape ofthe article to be made. In a preferred embodiment, the curing processmay be initiated after fabrication of the article by heating or othercuring initiation step as would be familiar to those skilled in the art.When using an external agent, such as high-energy radiation, to inducethe reaction, the propylene-based elastomer, or the blend comprising theelastomer, is fabricated into the final shape of the article to be madeprior to contact with the external agent.

Propylene-Based Elastomer

The propylene-based elastomer of the present invention is a randompropylene homopolymer or copolymer having crystalline regionsinterrupted by non-crystalline regions. The non-crystalline regions mayresult from regions of non-crystallizable polypropylene segments and/orthe inclusion of comonomer units. The crystallinity and the meltingpoint of the propylene-based elastomer are reduced compared to highlyisotactic polypropylene by the introduction of errors in the insertionof propylene and/or by the presence of comonomer.

The crystallinity of the propylene-based elastomer may be expressed interms of heat of fusion. In particular embodiments, the propylene-basedelastomer has a heat of fusion, as determined by DSC, ranging from alower limit of 1.0 J/g, or 1.5 J/g, or 3.0 J/g, or 4.0 J/g, or 6.0 J/g,or 7.0 J/g, to an upper limit of 30 J/g, or 40 J/g, or 50 J/g, or 60J/g, or 75 J/g.

The crystallinity of the propylene-based elastomer can also be expressedin terms of crystallinity percent. The thermal energy for the highestorder of polypropylene is estimated at 189 J/g. That is, 100%crystallinity is equal to 189 J/g. Therefore, in particular embodiments,the propylene-based elastomer has a propylene crystallinity within therange having an upper limit of 65%, or 40%, or 30%, or 25%, or 20%, anda lower limit of 1%, or 3%, or 5%, or 7%, or 8%.

The level of crystallinity is also reflected in the melting point. Theterm “melting point,” as used herein is the highest peak among principaland secondary melting peaks, as determined by DSC. In particularembodiments, the propylene-based elastomer has a melting point by DSCranging from an upper limit of 110° C., or 105° C., or 90° C., or 80°C., or 70° C. to a lower limit of 0° C., or 20° C., or 25° C., or 30°C., or 35° C., or 40° C., or 45° C.

The propylene-based elastomer generally comprises at least 60 wt %propylene-derived units, and in particular embodiments, thepropylene-based elastomer comprises at least 75 wt %, or at least 80 wt%, or at least 90 wt % propylene-derived units.

Propylene-based elastomers suitable in the present invention have anisotactic propylene triad tacticity within the range having a lowerlimit of 65%, or 70%, or 75% to an upper limit of 95%, or 97%, or 98%,or 99%. The isotactic propylene triad tacticity of a polymer is therelative tacticity of a sequence of three adjacent propylene units, achain consisting of head to tail bonds, expressed as a binarycombination of m and r sequences. The isotactic propylene triadtacticity of the polymers disclosed herein was determined using C¹³NMRand the calculations outlined in U.S. Pat. No. 5,504,172.

In particular embodiments, the propylene-based elastomer of theinvention has an isotacticity index greater than 0%, or within the rangehaving an upper limit of 50%, or 25% and a lower limit of 3%, or 10%.

In particular embodiments, the propylene-based elastomer of theinvention has a tacticity index (m/r) within the range having an upperlimit of 8, or 10, or 12, and a lower limit of 4, or 6.

In particular embodiments, the propylene-based elastomer of theinvention has a Melt Flow Rate (MFR) at 230° C. of from 0.1 to 400, orfrom 3 to 200, or from 5 to 150, prior to crosslinking.

In particular embodiments, the propylene-based elastomer has a tensionset after 200% elongation of less than 50%. In a particular aspect ofthis embodiment, the propylene-based elastomer has an ultimate tensilestrength of 1500 psi (10.4 MPa) or greater, or 1000 psi (6.9 MPa) orgreater, or 500 psi (3.5 MPa) or greater.

In some embodiments, the crystallinity of the propylene-based elastomeris controlled by the copolymerization of propylene with limited amountsof one or more comonomers selected from: ethylene, C₄-C₂₀ alpha-olefins,and polyenes. In these copolymers, the amount of propylene-derived unitspresent in the propylene-based elastomer ranges from an upper limit of99.9 wt %, or 97 wt %, or 95 wt %, or 94 wt %, or 92 wt %, or 90 wt %,or 85 wt % to a lower limit of 60 wt %, 68 wt %, or 70 wt %, or 71 wt %,or 75 wt %, or 76 wt %, or 80 wt %, based on the total weight of thepropylene-based elastomer. The amount of optional units derived fromethylene and/or C₄-C₂₀ alpha-olefins present in the propylene-basedelastomer ranges from an upper limit of 40 wt %, or 35 wt %, or 30 wt %,or 28 wt %, or 25 wt %, or 20 wt %, or 15 wt % to a lower limit of 0 wt%, or 0.5 wt %, or 1 wt %, or 2 wt %, or 3 wt %, or 5 wt %, or 6 wt %,or 8 wt %, or 10 wt %, based on the total weight of the propylene-basedelastomer. The amount of optional polyene-derived units present in thepropylene-based elastomer ranges from an upper limit of 25 wt %, or 20wt %, or 15 wt %, or 10 wt %, or 7 wt %, or 6 wt %, or 5 wt %, or 4.5 wt%, or 3 wt %, or 2.5 wt %, to a lower limit of 0 wt %, or 0.1 wt %, or0.2 wt %, or 0.3 wt %, or 0.5 wt %, or 1 wt %, or 1.5 wt % based on thetotal weight of the propylene-based elastomer.

Non-limiting examples of preferred α-olefin(s) optionally present in thepropylene-based elastomer include propylene, 1-butene, 1-pentene,1-hexene, 1-octene, and 1-dodecene. The polyene-derived units optionallypresent in the propylene-based elastomer may be derived from anyhydrocarbon structure having at least two unsaturated bonds wherein atleast one of the unsaturated bonds may be incorporated into a polymer.Non-limiting examples of preferred polyenes include5-ethylidene-2-norbornene (“ENB”), 5-vinyl-2-norbornene (“VNB”), divinylbenzene (“DVB”), and dicyclopentadiene (“DCPD”).

In a particular embodiment, the propylene-based elastomer has a Mooneyviscosity ML(1+4) at 125° C. of from 0.5 to 100, or from 5 to 40, orfrom 10 to 40.

The propylene-based elastomer of the invention has a weight averagemolecular weight (M_(w)) within the range having an upper limit of5,000,000 g/mol, or 1,000,000 g/mol, or 500,000 g/mol, and a lower limitof 10,000 g/mol, or 15,000 g/mol, or 20,000 g/mol, or 80,000 g/mol, anda molecular weight distribution M_(w)/M_(n) (MWD), sometimes referred toas a “polydispersity index” (PDI), within the range having an upperlimit of 40, or 20, or 10, or 5, or 4.5, or 4.0, or 3.2, or 3.0, and alower limit of 1.5, or 1.8, or 2.0.

Illustrative non-limiting examples of suitable propylene-basedelastomers, as well as the methods for preparing them, include the “FPC”disclosed in pending U.S. Provisional Patent Application No. 60/519,975;the “isotactic propylene copolymer” disclosed in U.S. Patent ApplicationPublication No. 2003/0204017; the “propylene ethylene copolymers”disclosed in U.S. Pat. No. 6,525,157; and the “propylene ethylenecopolymers” disclosed in PCT Publication No. WO02/083754, thedisclosures of which are hereby fully incorporated herein by reference.

Separate from, or in combination with the foregoing, the crystallinityof the propylene-based elastomer can be reduced also by stereo-irregularincorporation of the propylene-derived units, which can be influencedby, for example, the choice of catalyst and polymerization temperature.

The propylene-based elastomers of the present invention are not limitedby any particular polymerization method of preparation, and thepolymerization processes described herein are not limited by anyparticular type of reaction vessel.

In a particular embodiment, the catalyst system used to produce thepropylene-based elastomer includes one or more transition metalcompounds and one or more activators. When alumoxane or aluminum alkylactivators are used, the combined pre-catalyst-to-activator molar ratiois generally from 1:5000 to 10:1. When ionizing activators are used, thecombined pre-catalyst-to-activator molar ratio is generally from 10:1 to1:10. Multiple activators may be used, including using mixtures ofalumoxanes or aluminum alkyls with ionizing activators.

In another particular embodiment, the catalyst system includes abis(cyclopentadienyl) metal compound and either (1) a non-coordinatingcompatible anion activator, or (2) an alumoxane activator. Non-limitingexamples of catalyst systems which can be used are described in U.S.Pat. Nos. 5,198,401 and 5,391,629, which are hereby incorporated hereinby reference.

In another embodiment, the propylene-based elastomer is made in thepresence of an activating cocatalyst which is a precursor ionic compoundcomprising a halogenated tetra-aryl-substituted Group 13 anion whereineach aryl substituent contains at least two cyclic aromatic rings. In aparticular aspect of this embodiment, the propylene-based elastomercontains greater than 0.2 parts per million, or greater than 0.5 partsper million, or greater than 1 part per million, or greater than 5 partsper million of the residues of the activating cocatalyst.

In another particular embodiment, the catalyst system used to producethe propylene-based elastomer includes a Hf-containing metallocenecatalyst, such as but not limited to dimethyl silyl bis(indenyl) hafniumdimethyl, and a non-coordinating anion activator, such as but notlimited to dimethyl anilinium tetrakis(heptafluoronaphthyl) borate.

In yet another particular embodiment, the propylene-based elastomer isproduced using any of the catalyst systems and polymerization methodsdisclosed in U.S. Patent Application Publication 2004/0024146, thedisclosure of which is hereby incorporated herein by reference.

In yet another particular embodiment, the propylene-based elastomer isproduced using a catalyst system such as one of the nonmetallocene,metal-centered, heteroaryl ligand catalyst systems described in U.S.Patent Application Publication 2003/0204017, the disclosure of which ishereby incorporated herein by reference.

Further general process condition information suitable for use inpreparing the propylene-based elastomer can be found in disclosuresincluding, but not limited to U.S. Pat. No. 5,001,205 and PCTpublications WO96/33227 and WO97/22639. Further information on gas phasepolymerization processes can be found in disclosures including, but notlimited to U.S. Pat. Nos. 4,543,399; 4,588,790; 5,028,670; 5,317,036;5,352,749; 5,405,922; 5,436,304; 5,453,471; 5,462,999; 5,616,661;5,627,242; 5,665,818; 5,668,228; and 5,677,375, and Europeanpublications EP-A-0 794 200; EP-A-0 802 202; and EP-B-634 421.Information relating to methods of introducing liquid catalyst systemsinto fluidized bed polymerizations into a particle lean zone can befound in disclosures including, but not limited to U.S. Pat. No.5,693,727. Further information on slurry polymerization processes can befound in disclosures including, but not limited to U.S. Pat. Nos.3,248,179 and 4,613,484. PCT publication WO 96/08520 and U.S. Pat. No.5,712,352 are non-limiting examples of disclosures which describe apolymerization process operated in the absence of or essentially free ofany scavengers.

In embodiments of the invention including a composition comprising thepropylene-based elastomer, the propylene-based elastomer is present inan amount of at least 50 wt %, or at least 60 wt %, or at least 70 wt %,or at least 75 wt %, or at least 80 wt %, or at least 95 wt %, based onthe total weight of the composition.

In another embodiment of the invention including a compositioncomprising the propylene-based elastomer, the ratio of the total weightof the crystalline polymer component, fillers, pigments, andplasticizers, etc. (i.e., the total weight of the materials other thanthe propylene-based elastomer) to the weight of the propylene-basedelastomer is 2 or less, or 1.5 or less, or 1.3 or less, or 1 or less, or0.5 or less, or 0.3 or less, or 0.2 or less.

Crystalline Polymer Component

Some embodiments of the invention include a crystalline propylenepolymer component. The crystalline polymer component may be selectedfrom: propylene homopolymer, propylene copolymer, and mixtures thereofwhich are commonly known as reactor copolymers or impact copolymers. Inembodiments where the crystalline polymer component includes a propylenecopolymer, the propylene copolymer may be a graft copolymer, blockcopolymer, or random copolymer.

The amount of propylene-derived units present in the crystalline polymercomponent is 90 wt % or higher, or 92 wt % or higher, or 95 wt % orhigher, or 97 wt % or higher, or 100 wt %, based on the total weight ofthe crystalline polymer component.

In one embodiment, the crystalline polymer component includes a randomcopolymer of propylene and at least one comonomer selected from one ormore of: ethylene and C₄-C₁₂ alpha-olefins. In a particular aspect ofthis embodiment, the amount of comonomer is within the range having anupper limit of 9 wt %, or 8 wt %, or 6 wt %, and a lower limit of 2 wt%, based on the total weight of the crystalline polymer component.

The crystalline polymer component of the invention has a melting pointby DSC of at least 110° C., or at least 115° C., or at least 130° C.,and a heat of fusion, as determined by DSC, of at least 60 J/g, or atleast 70 J/g, or at least 80 J/g.

The crystalline polymer component of the invention has a weight averagemolecular weight (M_(w)) within the range having an upper limit of5,000,000 g/mol, or 500,000 g/mol, and a lower limit of 10,000 g/mol, or50,000 g/mol, and a molecular weight distribution M_(w)/M_(n) (MWD),sometimes referred to as a “polydispersity index” (PDI), within therange having an upper limit of 40 and a lower limit of 1.5.

The invention is not limited by any particular method for preparing thecrystalline polymer component. In one embodiment, the crystallinepolymer component may be a propylene homopolymer obtained by a wellknown process for the homopolymerization of propylene in a single stageor multiple stage reactor. In another embodiment, the crystallinepolymer component may be a propylene copolymer obtained by a well knownprocess for copolymerizing propylene and one or more comonomers in asingle stage or multiple stage reactor.

Polymerization methods for preparing the crystalline polymer componentinclude high pressure, slurry, gas, bulk, solution phase, andcombinations thereof. Catalyst systems that can be used includetraditional Ziegler-Natta catalysts and single-site metallocene catalystsystems. In one embodiment, the catalyst used has a high isospecificity.

Polymerization of the crystalline polymer component may be carried outby a continuous or batch process and may include the use of chaintransfer agents, scavengers, or other such additives well known to thoseskilled in the art. The crystalline polymer component may also containadditives such as flow improvers, nucleators, and antioxidants which arenormally added to isotactic polypropylene to improve or retainproperties.

Blends

In one embodiment, the invention provides a blend composition comprisingat least one propylene-based elastomer, and at least one crystallinepolymer component. Such blend compositions have a heterogeneous phasemorphology consisting of domains of different crystallinities. Thesedomains of different crystallinities differentiate the inventivecompositions from commonly available propylene reactor copolymers (i.e.,blends of isotactic polypropylene and copolymers of propylene andethylene), which have a single crystalline phase.

In the preferred embodiment, the continuous phase of the heterogeneousblend compositions has amorphous or crystallizable morphology, andcontains the propylene-based elastomer and may contain minor amounts ofthe crystalline polymer component. The dispersed phase has crystallinemorphology, and contains the crystalline polymer component, optionalfillers, and may also contain propylene-based elastomer in small amountsrelative to the continuous phase. The propylene-based elastomer has lowcrystallinity relative to the crystalline polymer component; therefore,the continuous phase of the inventive compositions has low crystallinityrelative to the dispersed phase. The low crystallinity continuous phasedifferentiates the most preferred embodiments of the inventivecompositions from commonly available propylene impact copolymers,thermoplastic elastomers, thermoplastic vulcanizates, and thermoplasticolefins, which have a highly crystalline continuous phase.

The components of the blend compositions should be selected to becompatible preferably to the extent that it is not be necessary to addpreformed or in-situ formed compatibilizer to attain and retain a fineblend morphology.

The domains of the dispersed phase of the preferred heterogeneous blendcompositions described herein are small with an average minimum axis ofless than 5 μm. The larger axis of the dispersed phase can be as largeas 100 μm.

Additives

As will be evident to those skilled in the art, the compositions of thepresent invention may comprise additives in addition to the polymercomponents. Various additives may be present to enhance a specificproperty or may be present as a result of processing of the individualcomponents. Additives which may be incorporated include, but are notlimited to processing oils, fire retardants, antioxidants, plasticizers,pigments, vulcanizing or curative agents, vulcanizing or curativeaccelerators, cure retarders, processing aids, flame retardants,tackifying resins, flow improvers, and the like. Antiblocking agents,coloring agents, lubricants, mold release agents, nucleating agents,reinforcements, and fillers (including granular, fibrous, orpowder-like) may also be employed. Nucleating agents and fillers mayimprove the rigidity of the article. The list described herein is notintended to be inclusive of all types of additives which may be employedwith the present invention. Those of skill in the art will appreciatethat other additives may be employed to enhance properties of thecomposition. As is understood by those skilled in the art, thecompositions of the present invention may be modified to adjust thecharacteristics of the blend as desired.

The compositions described herein may also contain inorganic particulatefillers, which may improve the mechanical and wear properties of thecompositions, particularly in compositions including cured components.The amount of inorganic filler used is typically from 1 to 100 parts byweight of inorganic filler per 100 parts of polymeric material. Theinorganic fillers include particles less than 1 mm in diameter, rodsless than 1 cm in length, and plates less than 0.2 cm² in surface area.Exemplary particulate fillers include talc, clays, titanium andmagnesium oxides, and silica. Carbon black will typically not bepreferred, as it interferes with desired optical properties. Inaddition, other particulate fillers, such as calcium carbonate, zincoxide, whiting, and magnesium oxide, can also be used. An example of arod-like filler is glass fiber. An example of a plate-like filler ismica. The addition of very small particulate fibers, commonly referredto as nanocomposites, is also contemplated. The addition of the fillersmay change the properties of the compositions described herein. Forexample, compositions including inorganic filler can yield improvedthermal stability and resistance to wear.

The amount and choice of filler is limited to those combinations whichdo not compromise the transparency of the crosslinked article.Typically, the addition of fillers leads to loss of clarity due toobstruction of the passage of light through polymer samples includingfiller. Several methods are available for inducing clarity in thepresence of filler including (a) the use of fillers whose lineardimensions are comparable to or smaller than the wavelength of visiblelight, (b) the use of transparent fillers whose refractive index issimilar to the propylene-based elastomer, and (c) using the minimumallowable amount of filler or pigment. In various embodiments of theinvention, one or more of these procedures may be used to maintainclarity of the inventive compositions.

The compositions described herein may contain process oil in the rangeof from 0 to 500 parts by weight, or from 2 to 200 parts by weight, orfrom 5 to 150 parts by weight, or from 10 to 100 parts by weight or from20 to 50 parts by weight, per hundred parts of total polymer. Theaddition of process oil in moderate amounts may lower the viscosity andflexibility of the blend while improving the properties of the blend attemperatures near and below 0° C. It is believed that these potentialbenefits arise by the lowering of the glass transition temperature (Tg)of the blend. Adding process oil to the blend may also improveprocessability and provide a better balance of elastic and tensilestrength. The process oil is typically known as extender oil in rubberapplications. Process oils include hydrocarbons having either (a) tracesof hetero atoms such oxygen or (b) at least one hetero atom such asdioctyl plithalate, ethers, and polyethers. Process oils have a boilingpoint to be substantially involatile at 200° C. These process oils arecommonly available either as neat solids, liquids, or as physicallyabsorbed mixtures of these materials on an inert support (e.g., clay,silica) to form a free flowing powder. Process oils usually include amixture of a large number of chemical compounds which may consist oflinear, acyclic but branched, cyclic, and aromatic carbonaceousstructures. Another family of process oils are certain organic estersand alkyl ether esters having a molecular weight (Mn) less than 10,000.Combinations of process oils may also be used in the practice of theinvention. The process oil should be compatible or miscible with thepolymer blend composition in the melt, and may be substantially misciblein the propylene-based elastomer at room temperature. Process oils maybe added to the blend compositions by any of the conventional meansknown in the art, including the addition of all or part of the processoil prior to recovery of the polymer, and addition of all or part of theprocess oil to the polymer as a part of a compounding for theinterblending of the propylene-based elastomer. The compounding step maybe carried out in a batch mixer, such as a mill, or an internal mixer,such as a Banbury mixer. The compounding operation may also be conductedin a continuous process, such as a twin screw extruder. The addition ofprocess oils to lower the glass transition temperature of blends ofisotactic polypropylene and ethylene propylene diene rubber is describedin U.S. Pat. Nos. 5,290,886 and 5,397,832, the disclosures of which arehereby incorporated herein by reference.

As used herein, the term “process oil” also includes certain hydrocarbonresins, which are selected to be miscible with the polymer. The resinsare miscible if they meet the following criteria. In a differentialscanning calorimetry (DSC) experiment, a polymer composition shows asingle glass transition temperature (Tg1) between 20° C. and −50° C.; acorresponding polymer blend containing the polymer composition andhydrocarbon resin also shows a single glass transition temperature(Tg2); and Tg2 is higher than Tg1 by at least 1° C. The resins useful asprocess oil in the present invention preferably have a glass transitiontemperature, by DSC, of 20° C. or greater.

Hydrocarbon resins useful in embodiments of the present invention have asoftening point within the range having an upper limit of 180° C., or150° C., or 140° C., and a lower limit of 80° C., or 120° C., or 125° C.The softening point (° C.) is measured as a ring and ball softeningpoint according to ASTM E-28 (Revision 1996).

In a particular embodiment, the blends of the present invention includea hydrocarbon resin in an amount ranging from a lower limit of 1%, or5%, or 10% by weight, based on the total weight of the blend, to anupper limit of 30%, or 25%, or 20%, by weight, based on the total weightof the blend.

Various types of natural and synthetic resins, alone or in admixturewith each other, can be used in preparing the compositions describedherein. Suitable resins include, but are not limited to, natural rosinsand rosin esters, hydrogenated rosins and hydrogenated rosin esters,coumarone-indene resins, petroleum resins, polyterpene resins, andterpene-phenolic resins. Specific examples of suitable petroleum resinsinclude, but are not limited to aliphatic hydrocarbon resins,hydrogenated aliphatic hydrocarbon resins, mixed aliphatic and aromatichydrocarbon resins, hydrogenated mixed aliphatic and aromatichydrocarbon resins, cycloaliphatic hydrocarbon resins, hydrogenatedcycloaliphatic resins, mixed cycloaliphatic and aromatic hydrocarbonresins, hydrogenated mixed cycloaliphatic and aromatic hydrocarbonresins, aromatic hydrocarbon resins, substituted aromatic hydrocarbons,hydrogenated aromatic hydrocarbon resins. As used herein, hydrogenatedincludes fully, substantially and at least partially hydrogenatedresins. Suitable aromatic resins include aromatic modified aliphaticresins, aromatic modified cycloaliphatic resin, and hydrogenatedaromatic hydrocarbon resins having an aromatic content of 1-30%,preferably 1-20%, more preferably 1-5%, and even more preferably lessthan 1 wt %. Any of the above resins may be grafted with an unsaturatedester or anhydride to provide enhanced properties to the resin. Examplesof grafted resins and their manufacture are described in PCTApplications PCT/EP02/10794, PCT/EP02/10795, PCT/EP02/10796, andPCT/EP02/10686, which are incorporated herein by reference for U.S.purposes. For additional description of resins, reference can be made totechnical literature, e.g., Hydrocarbon Resins, Kirk-Othmer,Encyclopedia of Chemical Technology, 4th Ed. v. 13, pp. 717-743 (J.Wiley & Sons, 1995).

Illustrative, non-limiting examples of suitable resins include EMPR 100,101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 116, 117, and 118resins, and EMFR resins, available from ExxonMobil Chemical Company. Thepreceding examples are illustrative only and by no means limiting.Embodimets of the present invention include resins having a molecularweight (Mn) less than that of the polymer. Preferably, the resin has amolecular weight (Mn) within the range having an upper limit of 1000 anda lower limit of 500.

The addition of process aids, such as a mixture of fatty acid ester orcalcium fatty acid soap bound on a mineral filler, to the compositionsdescribed herein may help the mixing of the composition and theinjection of the composition into a mold. Other examples of process aidsare low molecular weight polyethylene copolymer wax and paraffin wax.The amount of process aid used may be within the range of from 0.5 to 5parts by weight per 100 parts of polymer.

Adding antioxidants to the compositions described herein may improve thelong term aging. Examples of antioxidants include, but are not limitedto quinolein, e.g., trimethylhydroxyquinolein (TMQ); imidazole, e.g.,zincmercapto toluyl imidazole (ZMTI); and conventional antioxidants,such as hindered phenols, lactones, and phosphites. The amount ofantioxidants used may be within the range of from 0.001 to 5 parts byweight per 100 parts of polymer.

Treatment and Use of Blend

We have discovered that optical properties of the blends can be improvedby post blend treatment. In many embodiments, heating the blend canmarkedly improve the clarity. This heating can be done as part of theblending process or subsequent to the blending process. Preferably, itis done as part of the crosslinking step, when thermally activatedcross-linking agents are employed. For example, when crystallinepolypropylene is used as the crystalline polymer component of the blend(preferably, for example, Achieve 3854 available from ExxonMobilChemical Company of Houston, Tex.) we have found that heating the blendto at least 170° C. either during or following the crosslinking stepgreatly improves clarity. More specifically, we have found that it isbeneficial to raise the temperature to a level such that the crystallinepolymer component is substantially entirely melted. Preferably, thetemperature is raised to at least the temperature at which 99% of themelting has occurred in the DSC thermogram. Those skilled in the artwill appreciate that lower temperatures can be used in some applicationswith negligible or modest diminution in clarity. In some cases, 95% or90% melting will suffice.

While not wishing to be bound by theory, we believe that raising thetemperature of the blend to about or above the melting point of thecrystalline polymer yields considerable decrease in the crystal size ofthe crystalline polypropylene, within the propylene based elastomermatrix, thus imparting a great increase in clarity. In some applicationsthis heating step will best be performed during forming of the finishedarticle. In other applications it may be desirable to form the articleand then conduct this heating step after the article is formed. We alsobelieve that certain additives, especially polycyclic polymers such asEMPR 100 or 103, available from ExxonMobil Chemical Company of Houston,Tex., can improve clarity properties of the finished blend. They can beused in an amount equal to 10 to 500 wt % of the crystalline polymercomponent, most preferably 10 to 50 wt % of the crystalline polymercomponent.

Definitions and Test Methods

Comonomer content: The comonomer content and sequence distribution ofthe polymers can be measured using ¹³C nuclear magnetic resonance (NMR)by methods well known to those skilled in the art. Comonomer content ofdiscrete molecular weight ranges can be measured using methods wellknown to those skilled in the art, including Fourier Transform InfraredSpectroscopy (FTIR) in conjunction with samples by GPC, as described inWheeler and Willis, Applied Spectroscopy, 1993, vol. 47, pp. 1128-1130.

In the particular case of propylene-ethylene copolymers containinggreater than 75 wt % propylene, the comonomer content can be measured asfollows. A thin homogeneous film is pressed at a temperature of about150° C. or greater, and mounted on a Perkin Elmer PE 1760 infraredspectrophotometer. A full spectrum of the sample from 600 cm⁻¹ to 4000cm⁻¹ is recorded and the monomer weight percent of ethylene can becalculated according to the following equation: Ethylene wt%=82.585−111.987X+30.045X², where X is the ratio of the peak height at1155 cm⁻¹ and peak height at either 722 cm⁻¹ or 732 cm⁻¹, whichever ishigher.

Polyene content: The amount of polyene present in a polymer can beinferred by the quantitative measure of the amount of the pendant freeolefin present in the polymer after polymerization. Several proceduressuch as iodine number and the determination of the olefin content by H¹or ¹³C nuclear magnetic resonance (NMR) have been established. Inembodiments described herein where the polyene is ENB, the amount ofpolyene present in the polymer can be measured using ASTM D3900.

Isotactic: The term “isotactic” is defined herein as a polymer sequencein which greater than 50% of the pairs of pendant methyl groups locatedon adjacent propylene units, which are inserted into the chain in aregio regular 1,2 fashion and are not part of the backbone structure,are located either above or below the atoms in the backbone chain, whensuch atoms in the backbone chain are all in one plane. Certaincombinations of polymers in blends or polymer sequences within a singlepolymer are described as having “substantially the same tacticity,”which herein means that the two polymers are both isotactic according tothe definition above.

Tacticity: The term “tacticity” refers to the stereoregularity of theorientation of the methyl residues from propylene in a polymer. Pairs ofmethyl residues from contiguous propylene units identically insertedwhich have the same orientation with respect to the polymer backbone aretermed “meso” (m). Those of opposite configuration are termed “racemic”(r). When three adjacent propylene groups have methyl groups with thesame orientation, the tacticity of the triad is ‘mm’. If two adjacentmonomers in a three monomer sequence have the same orientation, and thatorientation is different from the relative configuration of the thirdunit, the tacticity of the triad is ‘mr’. When the middle monomer unithas an opposite configuration from either neighbor, the triad has ‘rr’tacticity. The fraction of each type of triad in the polymer can bedetermined and when multiplied by 100 indicates the percentage of thattype found in the polymer.

The triad tacticity of the polymers described herein can be determinedfrom a ¹³C nuclear magnetic resonance (NMR) spectrum of the polymer asdescribed below and as described in U.S. Pat. No. 5,504,172, thedisclosure of which is hereby incorporated herein by reference.

Tacticity Index: The tacticity index, expressed herein as “m/r”, isdetermined by ¹³C nuclear magnetic resonance (NMR). The tacticity indexm/r is calculated as defined in H. N. Cheng, Macromolecules, 17, 1950(1984). An m/r ratio of 1.0 generally describes a syndiotactic polymer,and an m/r ratio of 2.0 generally describes an atactic material. Anisotactic material theoretically may have a ratio approaching infinity,and many by-product atactic polymers have sufficient isotactic contentto result in ratios of greater than 50.

Melting point and heat of fusion: The melting point (Tm) and heat offusion of the polymers described herein can be determined byDifferential Scanning Calorimetry (DSC), using the ASTM E-794-95procedure. About 6 to 10 mg of a sheet of the polymer pressed atapproximately 200° C. to 230° C. is removed with a punch die andannealed at room temperature for 48 hours. At the end of this period,the sample is placed in a Differential Scanning Calorimeter (PerkinElmer Pyris Analysis System and cooled to about −50° C. to −70° C. Thesample is heated at about 20° C./min to attain a final temperature ofabout 180° C. to 200° C. The term “melting point,” as used herein, isthe highest peak among principal and secondary melting peaks asdetermined by DSC, discussed above. The thermal output is recorded asthe area under the melting peak of the sample, which is typically at amaximum peak at about 30° C. to about 175° C. and occurs between thetemperatures of about 0° C. and about 200° C. The thermal output ismeasured in Joules as a measure of the heat of fusion. The melting pointis recorded as the temperature of the greatest heat absorption withinthe range of melting of the sample.

Molecular weight and molecular weight distribution: The molecular weightand molecular weight distribution of the polymers described herein canbe measured as follows. Molecular weight distribution (MWD) is a measureof the range of molecular weights within a given polymer sample. It iswell known that the breadth of the MWD can be characterized by theratios of various molecular weight averages, such as the ratio of theweight average molecular weight to the number average molecular weight,Mw/Mn, or the ratio of the Z-average molecular weight to the weightaverage molecular weight Mz/Mw.

Mz, Mw, and Mn can be measured using gel permeation chromatography(GPC), also known as size exclusion chromatography (SEC). This techniqueutilizes an instrument containing columns packed with porous beads, anelution solvent, and detector in order to separate polymer molecules ofdifferent sizes. In a typical measurement, the GPC instrument used is aWaters chromatograph equipped with ultrastyro gel columns operated at145° C. The elution solvent used is trichlorobenzene. The columns arecalibrated using sixteen polystyrene standards of precisely knownmolecular weights. A correlation of polystyrene retention volumeobtained from the standards, to the retention volume of the polymertested yields the polymer molecular weight.

Average molecular weights M can be computed from the expression:

$M = \frac{\sum\limits_{i}^{\;}{N_{i}M_{i}^{n + 1}}}{\sum\limits_{i}^{\;}{N_{i}M_{i}^{n}}}$where N_(i) is the number of molecules having a molecular weight M_(i).When n=0, M is the number average molecular weight Mn. When n=1, M isthe weight average molecular weight Mw. When n=2, M is the Z-averagemolecular weight Mz. The desired MWD function (e.g., Mw/Mn or Mz/Mw) isthe ratio of the corresponding M values. Measurement of M and MWD iswell known in the art and is discussed in more detail in, for example,Slade, P. E. Ed., Polymer Molecular Weights Part II, Marcel Dekker,Inc., NY, (1975) 287-368; Rodriguez, F., Principles of Polymer Systems3rd ed., Hemisphere Pub. Corp., NY, (1989) 155-160; U.S. Pat. No.4,540,753; Verstrate et al., Macromolecules, vol. 21, (1988) 3360; andreferences cited therein.

Tension set: Tension set can be measured according to the general ASTMD790 procedure by uniaxially deforming a sample to differentelongations.

Stress relaxation: Stress relaxation can be measured using the followingprocedure. The sample is mounted on an Instron 4465 tester and elongatedto 200% elongation. The load at this elongation is measured as L1. Thesample is maintained at this extension for 30 seconds and the new loadat the end of the 30 seconds is measured as L1₃₀. The relaxation (R1) ofthe film is measured as 100×(L1−L1₃₀)/L1, and is expressed as apercentage. The sample is returned to the initial elongation of 0%. Thesample is then elongated to 200% elongation. The load at this elongationis measured as L2. The sample is maintained at this extension for 30seconds and the new load at the end of the 30 seconds is measured asL2₃₀. The relaxation (R2) of the film is measured as 100×(L2−L2₃₀)/L2,and is expressed as a percentage. The sample is returned to the initialelongation of 0%. The elongation at which the load on the sample is zeroon the second cycle is noted as the set %. The hysteresis in the sampleis designated as 100×(L1−L2)/L1, and is expressed as a percentage.

Stress strain measurements: The stress-strain elongation properties ofthe cured compounds described herein can be measured according to theASTM D790 procedure described as follows. Dumbbell shaped samples werefabricated into a cured pad molded into dimensions of 6 in×6 in andremoved with a die. The stress strain evaluation of the samples wasconducted on an Instron 4465 tester determined for blends at 20 in/min,made by Instron Corporation of Canton, Mass. The digital data wascollected in a file collected by the Series IX Material Testing Systemavailable from Instron Corporation and analyzed using Excel, aspreadsheet program available from Microsoft Corporation of Redmond,Wash.

PHR: The term “phr” is used herein to mean parts per hundred rubber orparts per hundred elastomeric polymer.

Extraction in refluxing xylene: Solubility in refluxing xylene is ameasurement of the amount of insoluble and unextractible propylene-basedelastomer and optional ethylene-based polymer in compositions containingcured propylene-based elastomer and cured ethylene-based polymer (ifpresent). The process for determining solubility in xylene is asfollows. A sample having a thin section, i.e., less than 0.5 in, andweighing approximately 2 grams is weighed, and the weight is recorded asW₁. The sample is exposed to 50 ml of refluxing xylene in an extractionapparatus. The temperature of the sample is maintained at or near 140°C. by the refluxing solvent. After 24 hours of extraction, the solventis decanted off and 50 ml of new solvent is added and the extraction isconducted under identical conditions for another 24 hours. At the end ofthis period, the sample is removed and dried in a vacuum oven at 100° C.for 24 hours. The sample is then cooled and weighed for a final weightwhich is recorded as W₂. The fraction of the polymer insoluble in xyleneat reflux is determined by the following formula: % crosslinked, byextraction=100×[W₂(1−F_(Fi))]/[W₁(1−F_(S)−F_(P)−F_(Fi))], where F_(S) isthe weight fraction of crystalline polymer component present in thecomposition, F_(P) is the weight fraction of plasticizer, process oil,and other low molecular weight materials present in the compositionwhich are extractible in refluxing xylene, and F_(Fi) is the weightfraction of filler and other inorganic material present in thecomposition which are normally inextractible in refluxing xylene.

Die C tear strength: Die C tear properties are reported in lb force/inaccording to the ASTM D624 version 00 procedure. The data herein is forpeak force and the average of three samples is reported as the averagedata. The original data may be multiplied by 0.175 to convert the unitsfrom lb force/in to kN/m.

Trouser tear: Trouser tear properties are reported in lb force/inaccording to the ASTM D624 version 00 procedure. The data herein is forpeak force and the average of three samples is reported as the averagedata. The original data may be multiplied by 0.175 to convert the unitsfrom lb force/in to kN/m.

Mooney viscosity: Mooney viscosity, as used herein, is measured asML(1+4)@125° C. according to ASTM D1646.

Melt flow rate and melt index The determination of the Melt Flow rate(MFR) and the Melt Index of the polymer is according to ASTM D1238 usingmodification 1 with a load of 2.16 kg. In this version of the method aportion of the sample extruded during the test was collected andweighed. The sample analysis is conducted at 230° C. with a 1 minutepreheat on the sample to provide a steady temperature for the durationof the experiment. This data expressed as dg of sample extruded perminute is indicated as MFR. In an alternative procedure, the test isconducted in an identical fashion except at a temperature of 190 C. Thisdata is referred to as MI@190 C. As used herein, MFR@230° C. refers tothe MFR of the composition comprising the propylene-based elastomer,optional crystalline polymer component, and optional additives otherthan curative additives prior to crosslinking.

Shore A and Shore D hardness The determination of the Shore A and ShoreD hardness of the polymer is according to ASTM D 2240. In this versionof the method a portion of the sample is tested at room temperature. Thedata is recorded 15 seconds after the indentation is created in thesample. As used herein, Shore A hardness is the Shore A hardness of thecrosslinked composition.

Isotacticity Index: The isotacticity index is calculated according tothe procedure described in EP 0374695A2. The IR spectra of a thin filmof the material is recorded and the absorbance at 997 cm⁻¹ and theabsorbance at 973 cm⁻¹ are determined. The quotient of the absorbance at997 cm⁻¹ to the absorbance at 973 cm⁻¹ is multiplied by 100 to yield theisotacticity index. In the determination of the absorbance at these twopositions the position of zero absorbance is the absorbance when thereis no analytical sample present in the sample beam.

Viscosity ratio: Rheological experiments were performed on the samplesbefore and after irradiation. Experiments were performed on aRheomterics ARES Rheometer using parallel plate geometry using 25 mmdiameter plates. Small amplitude oscillatory shear measurements wereperformed at 190° C. and 20% strain from 0.1 to 100 rad/s. The ratio ofthe viscosity of the samples at 0.1 rad/s after radiation to that beforeradiation is taken to be the viscosity ratio.

Haze: Haze was measured on a compression molded plaque of the compoundapproximately 50 to 90 thousandths of an inch thick. Haze is expressedas a percentage and is measured on a Hazegard Plus Hazemeter, with a CIEIlluminant C light source according to the procedure of ASTM D1003-00.

Thickness: Thickness was measured with a hand-held micrometer and isexpressed as mils or thousandths of an inch.

RPA measurement: Cure characteristics (torque and loss factor) weremeasured using an RPA 2000 (Rubber Processing Analyzer) from AlphaTechnologies, Akron, Ohio. About 5.5 g of compound were weighted andplace between two thin Mylar films and placed between the RPA dieplates. The measurements were carried out as a function of time atseveral constant temperatures, in steps of 10° C. The temperature rangesfrom 140 to 210° C., depending on the cure package used. Strain was setto 13.95% and frequency to 1 Hz. The samples were first conditioned for1 minute at the selected temperature and data collection lasted for 1hour. The output of the measurement consisted of the torque (S′), themodulus and the loss factor (tan δ) of the compound as a function oftime which were then stored for further processing and analysis.

EXAMPLES

Sunpar 150 is a process oil available from Sunoco Inc, Philadelphia, Pa.

Translink 37 is a surface treated kaolin clay from EngelhardCorporation, Iselin, N.J.

EMPR 103 and EMPR 100 are hydrocarbon resins commercially available fromExxonMobil Chemical Co., Houston, Tex.

Dicumyl peroxide (DiCup R) and triallyl cyanourate (TAC) arecommercially available from Aldrich Chemical Co., Milwaukee, Wis.

ESC PP 4292 (3 MFR), ESC Achieve 3854 (34 MFR), ESC PP 3155 (35 MFR),ESC 100 MFR (100 MFR), ESC PP 3505 (400 MFR), and PP Achieve 3936 (100MFR) are isotactic polypropylenes having the given MFR and are availablefrom ExxonMobil Chemical Co., Houston, Tex.

V2504, V3666, and V404 are ethylene-propylene copolymers commerciallyavailable from ExxonMobil Chemical Co., Houston, Tex.

Irganox 1076 is an antioxidant available from Novartis Corporation.

HVA-2 is a curing coagent available from E.I. DuPont de Nemours,Wilmington, Del.

SHF 101 is a synthetic oil available from ExxonMobil Chemical Co.,Houston, Tex.

The propylene-based elastomers in the following examples can be preparedaccording to the following procedure. In a 27 liter continuous flowstirred tank reactor equipped with a dual pitch blade turbine agitator,92 Kg of dry hexane, 34 Kg of propylene, 1.8 Kg of ethylene, 1.1 Kg of5-ethylidene-2-norbornene (ENB) are added per hour. The reactor isagitated at 650 rpm during the course of the reaction and is maintainedliquid full at 1600 psi pressure (gauge) so that all regions in thepolymerization zone have the same composition during the entire courseof the polymerization. A catalyst solution in toluene of 1.5610-3 gramsof dimethylsilylindenyl dimethyl hafnium and 2.4210-3 grams ofdimethylanilinium tetrakis(heptafluoronaphthyl) borate are added at arate of 6.35 ml/min to initiate the polymerization. An additionalsolution of tri-n-octyl aluminum (TNOA) is added to remove extraneousmoisture during the polymerization. The polymerization is conducted atapproximately 59° C. and the temperature is maintained during thepolymerization by adding pre-chilled hexane at a temperature between −3°C. and 2° C. The polymerization typically leads to the formation of 9.5Kg of polymer per hour. The polymer is recovered by two stage removal ofthe solvent, first by removing 70% of the solvent using a lower criticalsolution process as described in WO0234795A1, and then removing theremaining solvent in a LIST devolatization extruder. The polymer isrecovered as pellets of about ⅛ to ¼ inch in principal axes.

Example 1

A propylene-based elastomer containing 13.5 wt % ethylene, 2.1 wt %5-ethylidene-2-norbornene (ENB), and having an MFR@230° C. of 25 wasprepared according to the procedure above and then blended with theingredients according to Table 1 in an internal Brabender mixeroperating at about 50 rpm at a temperature of about 100° C. The compoundwas then rolled out into a smooth sheet. The compounded material wasthen vulcanized at 150° C. for 100 minutes in the form of a 8″×8″compression molded pad with a thickness of 0.125″. Samples of theappropriate geometry were removed from the vulcanized pad and analyzed.The results of the analysis are given in Table 1 below.

TABLE 1 1-1 1-2 1-3 1-4 1-5 1-6 1-7 1-8 Materials Used Propylene-basedelastomer, g 240 240 240 240 240 240 240 240 DiCup R, g 2.4 3.6 2.4 3.62.4 3.6 2.4 3.6 HVA-2, g 1.0 1.0 1.5 1.5 0 0 0 0 TAC, g 0 0 0 0 2.0 2.03.0 3.0 RPA Measurements temperature, ° C. 160 160 160 160 160 160 160160 S′ max, dNm 1.76 2.62 1.95 2.83 2.28 3.21 2.59 3.62 tan δ @ S′ max0.223 0.142 0.221 0.142 0.152 0.101 0.136 0.092 Properties TensileElongation @20″/min, room temp 50% strain, psi (MPa) 318 298 318 297 291285 306 269 (2.19) (2.05) (2.19) (2.05) (2.01) (1.97) (2.11) (1.85) 100%strain, psi (MPa) 365 345 362 341 333 333 350 317 (2.52) (2.38) (2.50)(2.35) (2.30) (2.30) (2.41) (2.19) 200% strain, psi (MPa) 391 375 388372 358 365 376 357 (2.70) (2.59) (2.68) (2.56) (2.47) (2.52) (2.59)(2.46) 500% strain, psi (MPa) 558 552 590 580 512 542 564 581 (3.85)(3.81) (4.07) (4.00) (3.53) (3.74) (3.89) (4.01) Ultimate Elongation, %891 875 867 846 872 840 860 736 (6.14) (6.03) (5.98) (5.83) (6.01)(5.79) (5.93) (5.07) Ultimate Tensile, psi 1454 1432 1500 1460 1323 14241483 1204 (MPa) (10.0)  (9.9)  (10.3)  (10.1)  (9.1)  (9.8)  (10.2) (8.3)  Die C Tear @ max 203 195 204 193 193 189 190 172 load, room temp,(35.6)  (34.2)  (35.8)  (33.8)  (33.8)  (33.1)  (33.3)  (30.2)  lbforce/in (kN/m) Hardness initial, shore A 70 65 67 67 68 71 70 70 %crosslinked, by extraction 95 99 89 90 99 98 97 98 MFR@230° C. 25 25 2525 25 25 25 25 (exclusive of curatives) Haze, % 20.1 24.3 22.1 19.5 23.624.7 34.9 30.7 Gauge Average, mils 83.6 79.3 87.8 83.8 79.0 77.5 78.777.7 Haze %/100 mil 24.0 30.6 25.2 23.3 29.9 31.9 44.3 39.5

Example 2

Various propylene-based elastomers having the properties given in Table2 were made according to the procedure above.

TABLE 2 isotactity heat of Melting wt % wt % MFR index fusion Point**EXAMPLE C₂ ENB @230° C. (%) (J/g) (° C.) 2-1 16.30 1.94 3.62 43 8.7 482-2 15.24 2.14 16.63 45 9 50 2-3 13.76 2.08 15.68 58 9 46/60 2-4 13.351.96 3.82 57 20.4 45/59 2-5 10.34 2.07 4.07 67 24.4 45/68 2-6 10.06 2.1816.33 67 40.2 45/70 2-7 8.02 2.05 20.67 74 46.3 45/76 2-8 14.84 2.0721.6 48 * * 2-9 14.23 2.02 4.01 49 * * 2-10 13.38 2.12 11.01 53 * * 2-1110.19 2.11 8.14 53 * * 2-12 7.96 2.17 35.42 70 * * 2-13 15.87 3.88 5.5445 * * 2-14 15.63 4.03 17.69 44 * * 2-15 11.96 4.06 17.6 56 22.0 46/502-16 10.50 4.02 19.97 67 * * * not measured **Where two numbers aregiven for the melting point, the first number represents the primary orlargest melting peak, and the second number represents the secondarymelting peak.

Example 3

Certain propylene-based elastomers from Example 2 were vulcanizedaccording to the formulations given in Table 3-1 and 3-2 using thefollowing procedure. The polymer was first mixed with the plasticizerand the filler at a temperature of approximately 135 to 145° C. for 10minutes in a Brabender internal mixer having an internal capacity ofabout 280 ml. 40 g of the mixture of the polymer and plasicizer wasremoved for the determination of MFR. The remainder of the mixture wascooled and mixed with the curatives at a temperature not to exceed 105°C. for 10 minutes. The material was then vulcanized at 150° C. for 100minutes under a 20 ton pressure in the form of a 8″×8″ compressionmolded pad with a thickness of 0.125″. Samples of the appropriategeometry were removed from the vulcanized pad and analyzed. The resultsof the analysis are given in Tables 3-1 and 3-2 below.

TABLE 3-1 EXAMPLE 3-1 3-2 3-3 3-4 3-5 3-6 3-7 Materials Used Example2-1, g 240 0 0 0 0 0 0 Example 2-2, g 0 240 0 0 0 0 0 Example 2-3, g 0 0240 0 0 0 0 Example 2-4, g 0 0 0 240 0 0 0 Example 2-5, g 0 0 0 0 240 00 Example 2-6, g 0 0 0 0 0 240 0 Example 2-7, g 0 0 0 0 0 0 240 DiCup R,g 2.9 2.9 2.9 2.9 2.9 2.9 2.9 TAC, g 3.7 3.7 3.7 3.7 3.7 3.7 3.7Properties Tensile Elongation @20″/min, room temp 50% strain, psi 82 91234 340 684 651 835 (MPa) (0.57) (0.63) (1.61) (2.34) (4.72) (4.49)(5.76) 100% strain, psi 103 113 274 385 669 646 778 (MPa) (0.71) (0.78)(1.89) (2.65) (4.61) (4.45) (5.36) 200% strain, psi 130 147 317 426 658626 749 (MPa) (0.90) (1.01) (2.19) (2.94) (4.54) (4.32) (5.16) 500%strain, psi 537 463 927 1207 1627 1463 1585 (MPa) (3.70) (3.19) (6.39)(8.32) (11.22)  (10.09)  (10.93)  Ultimate Elongation, % 563 550 582 578616 634 660 Ultimate Tensile, psi 867 886 1374 1688 2408 2222 2506 (MPa)(6.0)  (6.1)  (9.5)  (11.6)  (16.6)  (15.3)  (17.3)  Die C Tear @ maxload, room temp, 71 77 153 187 316 287 354 lb force/in (kN/m) (12.4) (13.5)  (26.8)  (32.8)  (55.4)  (50.3)  (62.1)  Hardness initial, shoreA 48 49 65 71 84 83 88 % crosslinked, by extraction 99 89 79 100+   8995 90 MFR@230° C. (exclusive of curatives) 3.62 16.63 15.68 3.82 4.0716.33 20.67 Haze, % 13.7 17.2 19.5 13.8 31.6 52.3 74.0 Gauge Average,mils 83.6 79.3 87.8 83.8 79.0 77.5 78.7 Haze %/100 mil 16.4 21.7 22.216.5 40.0 67.5 94.0

TABLE 3-2 EXAMPLE 3-8 3-9 3-10 3-11 3-12 3-13 3-14 Materials UsedExample 2-1, g 200 0 0 0 0 0 0 Example 2-2, g 0 200 0 0 0 0 0 Example2-3, g 0 0 200 0 0 0 0 Example 2-4, g 0 0 0 200 0 0 0 Example 2-5, g 0 00 0 200 0 0 Example 2-6, g 0 0 0 0 0 200 0 Example 2-7, g 0 0 0 0 0 0200 DiCup R, g 2.9 2.9 2.9 2.9 2.9 2.9 2.9 TAC,g 3.7 3.7 3.7 3.7 3.7 3.73.7 SHF 101, g 40 40 40 40 40 40 40 Properties Tensile Elongation@20″/min, room temp 50% strain, psi 71 61 147 196 447 431 575 (MPa)(0.49) (0.42) (1.01) (1.35) (3.08) (2.97) (3.96) 100% strain, psi 86 74175 235 496 484 613 (MPa) (0.59) (0.51) (1.21) (1.62) (3.42) (3.34)(4.23) 200% strain, psi 105 91 209 281 517 508 631 (MPa) (0.72) (0.63)(1.44) (1.94) (3.56) (3.50) (4.35) 500% strain, psi 265 256 488 687 983973 1124 (MPa) (1.83) (1.77) (3.36) (4.74) (6.78) (6.71) (7.75) UltimateElongation, % 672 656 701 607 759 714 730 Ultimate Tensile, psi 671 6321031 1018 1930 1671 1934 (MPa) (4.6)  (4.4)  (7.1)  (7.0)  (13.3) (11.5)  (13.3)  Die C Tear @ max load, room temp 55 45 101 131 238 228280 lb force/in, (kN/m) (9.6)  (7.9)  (17.7)  (23.0)  (41.7)  (40.0) (49.1)  Hardness initial, shore A 40 35 55 57 73 72 75 % crosslinked, byextraction 98 89 95 99 90 90 93 MFR@230° C. (exclusive of curatives) 9.826.9 30.0 10.2 8.9 28.7 32.8 Haze, % 15.8 16.8 17.3 16.7 31.1 34.3 42.3Gauge Average, mils 81.7 77.0 77.2 79.8 74.6 75.2 77.0 Haze %/100 mil19.3 21.8 22.4 20.9 41.7 45.6 54.9

Example 4

Certain propylene-based elastomers from Example 2 were blended withisotactic polypropylene according to the formulations given in Table 4.The polymer components were blended in a twin screw extruder with a L/Dof 30:1 at a temperature of 200° C. across the length of the barrel. Inaddition to the polymer components, the compositions of Example 4 eachcontained 500 ppm of Irganox 1076 as an antioxidant.

TABLE 4 EXAMPLE 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 4-9 4-10 4-11 4-12 4-134-14 4-15 4-16 Example 2-1, g 200 200 200 200 0 0 0 0 0 0 0 0 0 0 0 0Example 2-4, g 0 0 0 0 200 200 200 200 0 0 0 0 0 0 0 0 Example 2-5, g 00 0 0 0 0 0 0 200 200 200 200 0 0 0 0 Example 2-13, g 0 0 0 0 0 0 0 0 00 0 0 200 200 200 200 ESC PP 3155 30 0 0 0 30 0 0 0 30 0 0 0 30 0 0 0ESC 100MFR 0 30 0 0 0 30 0 0 0 30 0 0 0 30 0 0 ESC PP 3505 0 0 30 0 0 030 0 0 0 30 0 0 0 30 0 PP Achieve 3936 0 0 0 30 0 0 0 30 0 0 0 30 0 0 030

Example 5

Certain samples from Example 4 were vulcanized according to theformulations given in Tables 5-1 and 5-2 using the following procedure.The polymer materials were first mixed with the plasticizer and thefiller at a temperature of approximately 135 to 145° C. for 10 minutesin a Brabender internal mixer having an internal capacity of about 280ml. 40 g of the mixture of the polymer and plasicizer was removed forthe determination of MFR. The remainder of the mixture was cooled andmixed with the curatives at a temperature not to exceed 105° C. for 10minutes. The material was then vulcanized at 150° C. for 100 minutesunder a 20 ton pressure in the form of a 8″×8″ compression molded padwith a thickness of 0.125″. Samples of the appropriate geometry wereremoved from the vulcanized pad and analyzed. The results of theanalysis are given in Tables 5-3 and 5-4 below.

TABLE 5-1 EXAMPLE 5-1 5-2 5-3 5-4 5-5 5-6 5-7 5-8 Materials Used Example4-1, g 250 0 0 0 0 0 0 0 Example 4-2, g 0 250 0 0 0 0 0 0 Example 4-3, g0 0 250 0 0 0 0 0 Example 4-4, g 0 0 0 250 0 0 0 0 Example 4-5, g 0 0 00 250 0 0 0 Example 4-6, g 0 0 0 0 0 250 0 0 Example 4-7, g 0 0 0 0 0 0250 0 Example 4-8, g 0 0 0 0 0 0 0 250 EMPR 103, g 25 25 25 25 25 25 2525 DiCup R, g 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 TAC, g 3 3 3 3 3 3 3 3

TABLE 5-2 EXAMPLE 5-9 5-10 5-11 5-12 5-13 5-14 5-15 5-16 Materials UsedExample 4-9, g 250 0 0 0 0 0 0 0 Example 4-10, g 0 250 0 0 0 0 0 0Example 4-11, g 0 0 250 0 0 0 0 0 Example 4-12, g 0 0 0 250 0 0 0 0Example 4-13, g 0 0 0 0 250 0 0 0 Example 4-14, g 0 0 0 0 0 250 0 0Example 4-15, g 0 0 0 0 0 0 250 0 Example 4-16, g 0 0 0 0 0 0 0 250 EMPR103, g 25 25 25 25 25 25 25 25 DiCup R, g 2.4 2.4 2.4 2.4 2.4 2.4 2.42.4 TAC, g 3 3 3 3 3 3 3 3

TABLE 5-3 EXAMPLE 5-1 5-2 5-3 5-4 5-5 5-6 5-7 5-8 Properties TensileElongation @20″/min, room temp 50% strain, psi 248 213 229 260 458 448425 372 (MPa) (1.71) (1.47) (1.58) (1.79) (3.16) (3.09) (2.93) (2.56)100% strain, psi 297 253 272 304 504 490 459 404 (MPa) (2.05) (1.74)(1.88) (2.10) (3.47) (3.38) (3.16) (2.79) 200% strain, psi 376 308 338376 581 564 517 454 (MPa) (2.59) (2.12) (2.33) (2.59) (4.01) (3.89)(3.56) (3.13) 500% strain, psi 845 652 670 746 1153 1032 940 821 (MPa)(5.83) (4.50) (4.62) (5.14) (7.95) (7.12) (6.48) (5.66) UltimateElongation, % 657 707 692 682 718 711 803 790 Ultimate Tensile, psi 13641253 1186 1203 2071 1817 2028 1793 (MPa) (9.40) (8.64) (8.18) (8.29)(14.28)  (12.53)  (13.98)  (12.36)  Die C Tear @ max load, room temp, lbforce/in 162 146 171 172 257 260 255 229 (kN/m) (28.4)  (25.6)  (30.0) (30.2)  (45.1)  (45.6)  (44.7)  (40.1)  Hardness initial, shore A 65 6162 69 74 78 76 77 % crosslinked, by extraction 85 97 98 98 95 90 93 87MFR@230° C. (exclusive of curatives) 6.3 6.2 7.8 24.6 7.1 6.8 7.2 6.5Haze, % 16.4 16.8 37.5 62.2 26.2 16.1 14.0 11.8 Gauge Average, mils 71.972.6 72.4 72.9 72.6 74.1 72.8 73.5 Haze %/100 mil 22.8 23.1 51.8 85.336.1 21.7 19.2 16.1

TABLE 5-4 EXAMPLE 5-9 5-10 5-11 5-12 5-13 5-14 5-15 5-16 PropertiesTensile Elongation @20″/min, room temp 50% strain, psi 757 750 747 683206 228 164 174 (MPa) (5.22) (5.17) (5.15) (4.71) (1.42) (1.57) (1.13)(1.20) 100% strain, psi 754 741 736 677 258 287 203 210 (MPa) (5.20)(5.11) (5.07) (4.67) (1.78) (1.98) (1.40) (1.45) 200% strain, psi 786767 765 695 344 386 268 262 (MPa) (5.42) (5.29) (5.27) (4.79) (2.37)(2.66) (1.85) (1.81) 500% strain, psi 1287 1242 1247 1156 810 873 704517 (MPa) (8.87) (8.56) (8.60) (7.97) (5.58) (6.02) (4.85) (3.56)Ultimate Elongation, % 725 726 728 717 661 621 623 437 Ultimate Tensile,psi 2140 2113 2116 1970 1434 1298 1135 455 (MPa) (14.75)  (14.57) (14.59)  (13.58)  (9.89) (8.95) (7.83) (3.14) Die C Tear @ max load,room 368 364 375 335 152 154 124 119 temp, lb force/in (64.5)  (63.8) (65.7)  (58.7)  (26.6)  (27.0)  (21.7)  (20.9)  (kN/m) Hardness initial,shore A 84 87 87 84 60 65 58 58 % crosslinked, by extraction 90 89 97 9693 98 99 100 MFR@230° C. 9.1 8.5 9.6 9 13.7 12.9 10.5 10.8 (exclusive ofcuratives) Haze, % 17.9 11.5 20.4 16.0 40.7 15.0 9.8 12.1 Gauge Average,mils 74.9 75.3 72.0 73.2 74.0 75.0 71.8 72.1 Haze %/100 mil 23.9 15.328.3 21.9 55.0 20.0 13.6 16.8

All patents, test procedures, and other documents cited herein,including priority documents, are fully incorporated by reference to theextent such disclosure is not inconsistent with this invention and forall jurisdictions in which such incorporation is permitted.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the invention, includingall features which would be treated as equivalents thereof by thoseskilled in the art to which the invention pertains.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated.

1. A heat-treated elastomeric blend compound, comprising: a continuousphase comprising: a propylene based material having 70-99.9 wt %propylene derived units, 5-25 wt % ethylene derived units, and 0.1-10 wt% diene derived units; and a dispersed phase comprising: a crystallinepolypropylene material having at least 96 wt % propylene derived units;and from 1% to 30% by weight, based on the total weight of the blend, ofa hydrocarbon resin exhibiting an Mn of from 500 to 1000; and whereinsaid elastomeric blend compound has a haze % of 30 or less per 100 milthickness; wherein said propylene based material has an isotacticpropylene triad tacticity in the range of from 65 to 95% and a heat offusion of from 5 J/g to 50 J/g as measured prior to blending with saidcrystalline polypropylene component, and the continuous elastomericphase is crosslinked and envelops domains of the dispersed thermoplasticphase; and wherein the elastomeric blend compound is heated to at leastthe temperature at which 99% of the melting of the crystallinepolypropylene component has occurred in a DSC thermogram during orsubsequent to crosslinking of the compound.
 2. The elastomeric blendcompound of claim 1 wherein said crystalline polypropylene material hasat least 98 wt % propylene derived units.
 3. The elastomeric blendcompound of claim 1 wherein said crystalline polypropylene material isisotactic homopolypropylene.
 4. The elastomeric blend compound of claim1 wherein said propylene based material has from 80-99.9 wt % propylenederived units and from 6-25 wt % ethylene derived units.
 5. Theelastomeric blend compound of claim 1 wherein said elastomeric compoundhas a haze % of 20 or less per mil thickness.
 6. The elastomeric blendcompound of claim 1 wherein said hydrocarbon resin is present in anamount of from 5% to 25% by weight, based on the total weight of theblend.
 7. A heat-treated crosslinked elastomeric blend, comprising: acontinuous elastomeric phase comprising: a propylene based materialhaving: 70-99.9 wt % propylene derived units, 5-25 wt % ethylene derivedunits, and 0.1-10 wt % diene derived units; and a dispersedthermoplastic phase comprising: a crystalline polypropylene materialhaving: at least 96 wt % propylene derived units, from 1% to 30% byweight, based on the total weight of the blend, of a hydrocarbon resinexhibiting an Mn of from 500 to 1000, wherein said crosslinkedelastomeric blend has a haze % of 30 or less per 100 mil thickness, thepropylene based material has an isotactic propylene triad tacticity offrom 65 to 95% and a heat of fusion of from 5 J/g to 50 J/g, as measuredprior to blending with said crystalline polypropylene component andprior to crosslinking, and the continuous elastomeric phase iscrosslinked and envelops domains of the dispersed thermoplastic phase;and wherein the elastomeric blend compound is heated to at least thetemperature at which 99% of the melting of the crystalline polypropylenecomponent has occurred in a DSC thermogram during or subsequent tocrosslinking of the compound.
 8. The blend of claim 7, wherein theelastomeric phase has an MFR (2.16 kg@230° C. of from 5 to 150 prior tocrosslinking.
 9. The blend of claim 7, wherein said crystallinepolypropylene material has at least 98 wt % propylene derived units. 10.The blend of claim 7, wherein said crystalline polypropylene material isisotactic homopolypropylene.
 11. The blend of claim 7, wherein saidpropylene based material has from 80-99.9 wt % propylene derived unitsand from 6-25 wt % ethylene derived units.
 12. The blend of claim 7,wherein the crosslinked elastomeric blend has a haze % of 20 or less per100 mil thickness.
 13. An article comprising the blend of claim
 7. 14.The article of claim 13, wherein the article is an extruded article. 15.The article of claim 13, wherein the article is a molded object.
 16. Anarticle comprising the blend of claim
 1. 17. The article of claim 1,wherein the article is an extruded article.
 18. The article of claim 1,wherein the article is a molded object.
 19. The elastomeric blendcompound of claim 1, wherein the elastomeric blend compound has beenheated to at least about 170° C.
 20. The crosslinked elastomeric blendof claim 7, wherein the elastomeric blend compound has been heated to atleast about 170° C.